Structural sandwich plate members

ABSTRACT

Various rolled or extruded profiles ( 1   c,    1   d ) with weld locations are used to connect together structural sandwich plate members comprising first and second outer metal plates ( 21 ) and an elastomer core ( 22 ) bonded to said outer metal plates ( 21 ) with sufficient strength to transfer shear forces therebetween.

This is a U.S. national phase application under 35 U.S.C. §371 ofInternational Patent Application No. PCT/GB02/00157, filed Jan. 15,2002. The International Application was published in English on Sep. 6,2002 as WO 02/068186 A1 under PCT Article 21 (2).

The present invention relates to structural sandwich plate members whichcomprise two outer metal plates and a core of plastic or elastomermaterial bonded to the outer metal plates with sufficient strength tosubstantially contribute to the structural strength of the member.

Structural sandwich plate members are described in U.S. Pat. No.5,778,813 and U.S. Pat. No. 6,050,208, which documents are herebyincorporated by reference, and comprise outer metal, e.g. steel, platesbonded together with an intermediate elastomer core, e.g. of unfoamedpolyurethane. These sandwich plate systems may be used in many forms ofconstruction to replace stiffened steel plates and greatly simplify theresultant structures, improving strength and structural performance(stiffness, damping characteristics) while saving weight. Furtherdevelopments of these structural sandwich plate members are described inInternational Patent Application GB00/04198, also incorporated hereby byreference. As described therein, foam forms may be incorporated in thecore layer to reduce weight and transverse metal sheer plates may beadded to improve stiffness.

The structural members described in the documents referred to abovegenerally are simple planar members which may be flat or curved (singleor double curvature) and which are welded together on site to form thedesired structure, e.g. a ship, offshore structure or bridge or othercivil engineering structure. In general, ships, offshore structures orcivil engineering works constructed with structural sandwich platemembers will be fabricated by first welding together the steelwork ofthe largest practicable section, a hull module for example, containingone or more internal airtight cavities. The elastomer is then injectedinto those cavities and cured making the section composite. Wherepanels, sections or modules are connected to form larger or completestructures, weld margins (free of elastomer) must be incorporated tomitigate or prevent damage to the elastomer from heat caused by thewelding process. When steel plates of adjacent modules containingstructural sandwich plate members are welded together the weld marginsform joining cavities. Once all welding is complete, elastomer isinjected into the joining cavities to make the structure continuouscomposite construction. This method of construction places the curedelastomer away from sections or plates being welded. Whilst this methodprovides satisfactory results, some simplification of this constructionmethod is desirable.

It is an aim of the present invention to provide structural sandwichplate members that can more easily be assembled into ships, shipcomponents, bridges and other civil engineering or offshore structures.

According to the present invention there is provided a structuralsandwich plate member comprising: first and second outer metal plates;an elastomer core bonded to said outer metal plates with sufficientstrength to transfer shear forces therebetween; and an edge memberformed by a rolled or extruded profile fitted between and connected tosaid first and second outer metal plates and extending along at least apart of the periphery of said outer metal plates and said profileproviding a weld location suitable for welding said structural sandwichplate member to another structural sandwich plate member.

The materials, dimensions and general properties of the outer metalplates of the structural sandwich plate member of the invention may bechosen as desired for the particular use to which the structuralsandwich plate member is to be put and in general may be as described inU.S. Pat. No. 5,778,813 and U.S. Pat. No. 6,050,208. Steel is commonlyused in thicknesses of 2 to 20 mm and aluminium may be used where lightweight is desirable. Similarly, the elastomer may be any suitable, e.g.plastics, material such as polyurethane, as described in U.S. Pat. No.5,778,813 and U.S. Pat. No. 6,050,208.

The rolled or extruded profiles can be made in various forms to beintegrated into the structural sandwich plate member to allow members tobe prefabricated and made continuous into larger structures by weldingmembers together at the weld locations or members to metal plates(without compromising the structural integrity), simplifying in situconstruction.

Profiles according to the present invention are made with rounds,fillets, dimensions and other features to provide good fatigue-resistantconnection details, connections with excellent dimensional control forease of fit up (mating of joining members) and built in weldpreparations (full or partial penetration weld preparations, backingbars and/or alignment plates) to reduce fabrication costs and tofacilitate in situ welding.

Weld locations based on the profile geometry, are located sufficientlyaway from the core material so that the welds can be made toprefabricated members without damaging the core or being detrimental tothe member's structural characteristics. Weld locations are also locatedaway from local high stress regions which may suffer fatigue problems.

Stiff edge profiles provide dimensional control for joining largesections or modules that advantageously eliminates the time-consumingand expensive heat faring processes associated with stiffened plateconstruction. Increased bending stiffness along joins between structuralsandwich plate members mitigates local weld distortions which simplifiesweld details and procedures, and reduces fabrication costs.

Profiles with built-in shear keys, alignment plates and friction connectjoints simplify fit-up, thereby reducing fabrication time, labour andcost.

Profile geometries according to the present invention have beendeveloped to provide good details for typical connections between platemembers in ships, maritime, civil and offshore structures. Profiles areidentified herein by a letter or letters which classify the type ofjoint, followed by a pair of numbers indicating a critical dimension andthe approximate mass of the profile in kilograms per metre of length.For example, E 40×17 is a typical edge profile for a structural sandwichplate member with a 40 mm thick core and has a mass of 17 kg/m. Thefollowing table lists some exemplary profile types, gives a briefdescription and describes their application or use.

Profile Type Description/Use E Edge or perimeter profile for connectinglarge sections or modules that require alignment of ± 5 mm alongmatching edges on sections measuring up to 50 m by 70 m in cross-section or weighing up to 500 T. SM, SF Male and female socket profilesfitted around the perimeter of structural sandwich plate members toconnect plate members directly to form larger plate members orindirectly through SP or CP profiles. P Plate profile which isintegrated into structural sandwich plate members and is used to connectto all-metal webs of transverse and longitudinal girders or bulkheads. TT Integral through-thickness plate profile for transferring forcedirectly through the structural sandwich plate member. S Spacer profileto connect and properly space at the specified core thickness metalplates to form structural sandwich plate members. Spacer profilesprovide a landing plate combination backing bar for welding plate seams.SP Sandwich panel profiles which are typically used to connectstructural sandwich panel members together to form larger sections ormodules, for example decks to side-shell or hull structure to bulkheads.CP Complex profiles for connecting multiple structural sandwich andmetal plate members. Geometries are specific to the given application.Typical examples include: inner bottom/hopper/girder; hopper/sideshell/web frame; and stool/inner hull/transverse floor connections. TTransition profiles for connecting existing metal plates to structuralsandwich plate members or as a transition section for a structuraloverlay.

Structural sandwich plate members according to the invention may containone or more cavities and one or more profile types as required for theapplication and the method by which they are to be connected (welded) toform the complete ship or structure.

The structural profiles, shapes or sections of the invention aregenerally roll-formed from steel or extruded from aluminium and willalmost always be of the same metal as that used to form the outer platesof the structural sandwich plate members of which they form part. Theprofiles are generally elongate and extend for substantially all of theperimeter, length and/or width of the structural sandwich plate membersand/or metal plates which they join.

It should be noted that the various profiles according to the inventionmay be used with structural sandwich plate members as described in thedocuments referenced above as well as those according to the presentinvention.

The present invention will be described below with reference toexemplary embodiments and the accompanying drawings, in which:

FIGS. 1A to C are cross-sections of edge profiles used in structuralsandwich plate members according to the present invention;

FIGS. 2A and B are cross-sectional views illustrating two ways in whichthe edge profiles of FIG. 1C can be used to connect modules comprised ofstructural sandwich plate members or structural sandwich plate membersaccording to the present invention;

FIGS. 3A and B are cross-sectional views illustrating deep male andfemale socket profiles according to the present invention and theirmanner of use;

FIGS. 4A and B are cross-sectional views illustrating shallow male andfemale socket profiles according to the present invention and theirmanner of use;

FIGS. 5A to D are cross-sectional views illustrating various plateprofiles for connecting structural sandwich plate members to aperpendicular metal plate;

FIG. 6 is a cross-sectional view illustrating a through-thickness plateprofile for direct force transmission;

FIGS. 7A and B are cross-sectional views illustrating two alternativespacer profiles for constructing structural sandwich plate membersaccording to the present invention;

FIGS. 8A to G illustrate various structural sandwich panel profiles forjoining together multiple prefabricated structural sandwich platemembers, e.g. members used to form the deck and side shell connections,bulkhead to hull connections of a bulk carrier, container vessel,tanker, etc., and their manner of use;

FIGS. 9A to J are cross-sectional views of various complex profilesaccording to the present invention and their manner of use forconnecting multiple structural sandwich plate members and metal platesor multiple structural sandwich plate members at acute and obtuseangles;

FIGS. 10A to D are cross-sectional views of transition profiles fortransition connections between a structural sandwich plate member and aconventional stiffened metal plate;

FIG. 11 is a mid-tank cross-section of a product oil tanker constructedusing structural sandwich plate members according to the presentinvention and identifies the type and location of different profiles;

FIG. 12 is a mid-tank longitudinal section of the product oil tanker ofFIG. 11;

FIG. 13 is an exploded view showing the structural components of amid-tank section of the product oil tanker of FIG. 11;

FIG. 14 is a partly-exploded perspective view with enlarged portionsshowing a structural sandwich plate member with integrated structuralprofiles according to the present invention and its connection to alongitudinal upstanding metal web; and

FIG. 15 is a partly-sectioned perspective view of two mid-tank sectionsof the product oil tanker of FIG. 11 which illustrates edge profiles andtheir manner of use for connecting two tank section modules.

In the various drawings, like references denote like parts.

FIGS. 1A to C illustrate edge profiles 1 a to c which generally form theoutward edge of a structural sandwich plate member such that, when anumber of such plate members are formed into a large section or module,the outward edge of that module is largely comprised of edge profilesthat can be mated and joined by welding the welding location on theoutward edge of an adjacent module. In general, the edge profilesinclude built-in backing bars and full or partial penetration grooveweld preparations at the possible weld locations to eliminate the needof providing or making these in situ. These sections may be roll formedor fabricated from standard shapes and plates in steel. Alternativelythey may be extruded in aluminium for applications where light weight isdesired, e.g. the upper decks of cruise ships or for hull forms in fastships. Of course, other metals may be used if desired and structuralprofiles of different metals may be used together to form structuralsandwich plate members according to the invention.

The edge profile 1 a shown in FIG. 1A, which is a lateral cross-section,comprises a generally planar portion (long flange) 11 which will formpart of one outer plate of a structural sandwich plate member and hassufficient length that the tip can be displaced (e.g. by up to ±5 mm) tobe aligned with the adjacent module. Placed inwardly from one edge ofthe section is an upstanding web 12 which will extend across thethickness of the structural sandwich plate member. At the distal end ofthe upstanding web 12, a short flange 13 parallel to the long flange 11and extending towards its centre is provided. Short flange 13 provides alanding surface for the metal plate used to complete the structuralsandwich plate member. Full penetration groove weld preparations 14 areprovided at the edges of the long flange 11 to enable an adjacent plateor edge profile to be welded to the edge profile from the exterior. Ascan be seen in the subsequent description, possible weld locationsinclude the full penetration groove weld preparations 14 and the end ofthe short flange 13.

FIG. 1B illustrates an alternative edge profile 1 b similar to that ofFIG. 1A and again comprising a plate portion (long flange) 11,upstanding web 12 and short flange 13. In this case, the weldpreparations 14 of the long flange 11 enable an adjacent plate or likesection to be welded to the edge profile 1 b from the interior. FIG. 1Cillustrates a further alternative edge profile 1 c which again consistsof (long flange) plate portion 11, upstanding web 12 and short flange 13performing the same functions as in the sections 1 a, 1 b of FIGS. 1Aand B. In edge profile 1 c of FIG. 1C, the upstanding web 12 is locatedadjacent one side edge of the long flange 11. The edge weld preparation14 on the other side may be arranged to enable welding from theexterior, as shown, or to enable welding from the interior, as desiredfor the intended fabrication sequence. At the base of the upstanding web12, a small projection 17 is provided, with its lower surface alignedwith the inner surface of the long flange 11, to act as a backing bar toreceive an adjacent plate. As can be seen in the subsequent description,possible weld locations include the small projection 17, weldpreparation 14 and the short flange 13.

It should be noted that in the above and following descriptions, theterms “interior” and “exterior” are used to identify preferred welddirection with respect to their intended location in a structure. InFIGS. 1A to C, the exterior surface of the profile is the lower surfaceand the interior, the upper surface.

FIGS. 2A and B illustrate two alternative ways in which profiles asshown in FIG. 1C can be used to connect large sections or modulescomprised of structural sandwich plate members.

In the arrangement of FIG. 2A, two sections or modules 2 a, 2 b areconstructed of structural sandwich plate members comprising outer metalplates 21 bonded together by an elastomer core 22 which substantiallycontributes to the structural strength of the member. The edges of thesections 2 a, 2 b are closed by an edge profile 1 c, one section 2 a hasthe long flange 11 of the edge profile 1 c downwards (as illustrated)and the other section 2 b has the planar portion 11 upwards (asillustrated). The two sections 2 a, 2 b are fitted together with thefree end of the long flange 11 of each edge profile 1 c supported by theshort flange 13 of the other edge profile 1 c. Full penetration groovebutt welds 4 b are made to connect the adjacent modules together at theweld location. The newly-formed cavity 5 is then injected with elastomerto make the construction continuous. If necessary, the degree of overlapbetween the short flange 13 of one section and the long flange 11 of theother can be varied to accommodate normal variations in fit-up that areassociated with making modules.

In the arrangement of FIG. 2B, two like edge profiles 1 d similar tothat shown in FIG. 1C are again used. In this case, the edge profiles 1d are positioned with their long flanges 11 on the same side. The weldpreparation as shown in FIG. 2B allows the finishing butt weld 4 b to bemade at the weld location from the interior. Subsequently plate 6, whichpreferably has the same thickness as the outer plates 21 of modules 2 a,2 b, is welded 4 b at the weld location to close cavity 5, with theshort flanges 13 acting as landing surfaces and backing bars. Cavity 5is then injected with elastomer to make the connecting plate segmentcomposite. This method of connection between modules allows for greatervariations in alignment than the method of FIG. 2A.

In FIGS. 2A and 2B, as well as various of the other figures describedbelow, butt welds made prior to casting of elastomer for the structuralsandwich plate members are indicated at 4 a. Finishing welds, that joinstructural profiles and plate members, are indicated at 4 b but not allare shown completed.

FIGS. 3A and B illustrate the deep male and female socket profiles andtheir use to align and join adjacent structural sandwich plate members.

As shown in FIG. 3A a male socket profile 71 and female socket profile72 have complimentary U-shapes that mate, providing alignment and shearcapacity between joining prefabricated structural sandwich platemembers. The total depth of the webs of the male and female socketprofiles 71, 72 are equal to the core thickness of the sandwich platemember in the edge of which they are fitted. As shown, the twostructural sandwich plate members have the same thickness but the socketprofiles may be varied to connect together structural sandwich platemembers of different thicknesses or different metal plate thicknesses.The socket profiles may extend for some or preferably all of the entirelengths of the edges of the structural sandwich plate members and arewelded to metal plates 21 by fillet welds 4 a as illustrated in FIG. 3Bto form metal boxes with enclosed air-tight cavities. Other profiles mayalso be integrated into the cavities or used along the edges. Thesecavities are injected with elastomer 22 and after curing form structuralsandwich plate members. Larger sections can be made by mating the maleand female socket profiles 71, 72 along the edges of adjacent platemembers at the weld locations, as shown in FIG. 3B and making themcontinuous by welding butt welds (not shown). The deep socket profilesneed not be fully butted, as shown in FIG. 3B, but may have a gapbetween profiles to accommodate misalignment within the plane of theplate members.

FIGS. 4A and B illustrate shallow male and female socket profiles 73, 74which form one or more edges of a structural sandwich plate member andare used in the same manner as the deep socket profiles 71, 72.

FIGS. 5A to D illustrate various plate profiles that are integrated intostructural sandwich plate members and that are used to connectstructural sandwich plate members that are in general perpendicular to ametal web.

FIG. 5A illustrates the basic form of a plate profile 81. The lower partof the profile 81 is shaped like an I-beam with upper and lower flanges811, 812. A web extends above the upper flanges. The flanges 811, 812act as landing surfaces and backing bars to allow the outer metal plates21 of structural sandwich plate members 2 a, 2 b to be welded to theplate profile 81 with butt or full penetration groove welds 4 a. The webextending above the upper flanges 811 is used as a weld location toconnect to the perpendicular metal web.

Subsequent to welding of all edge and integrated profiles to plates 21,elastomer 22 is injected into the cavities to form the structuralsandwich plate members 2 a, 2 b. Conventional metal plates or webs 61are welded to the plate profile 81 at the weld location with either fullpenetration groove welds or butt welds 4 b that are located sufficientlyaway from the core as not to damage it by the welding process.

Variations of the plate profile form with different dimensions, built-inweld preparations, backing bar and alignment plate arrangements areillustrated in FIGS. 5B, 5C and 5D. Plate profiles 82 and 83, shown inFIG. 5B and 5C respectively, are simplified and have one set of landingsurfaces/backing bars for the interior one of plates 21. The profile isfillet welded to the exterior one of plates 21 and welded to the web 61at the weld location with either a one-sided full penetration grooveweld or with two-sided partial penetration groove welds. The plateprofile 84 shown in FIG. 5D is similar to profile 82 but has anadditional backing bar alignment plate 842 to facilitate the welding ofthe web 61 at the weld location.

FIG. 6 illustrates a through-thickness profile 85 which can be used totransfer force directly through structural sandwich plate members. Thethrough-thickness profile 85 comprises a plate of constant thicknessfrom which project two spaced apart pairs of flanges 851, 852. Theseflanges 851, 852 act as landing surfaces and backing bars for plates 21forming the outer plates of structural sandwich plate elements 2 a, 2 bwhich are welded to it. Webs or other conventional metal plates can bewelded at weld locations to the through-thickness profile 85 of theprecast structural sandwich panel during construction.

Spacer profiles 91 and 93, shown in FIGS. 7A and 7B, can be used to actas a landing surface and backing bar 92 for making plate seams and tospace apart plates 21 which form the outer plates of structural sandwichplate members. Spacer profiles 91 and 93 are I-shaped and T-shapedrespectively. Each is first welded with fillet welds to the exteriorplate and then to the interior plates at a weld location when the plateseam is welded.

Various sandwich plate profiles 101 to 107 for joining mutuallyperpendicular structural sandwich plate members are shown incross-section in FIG. 8A, whilst their manner of use is shown in FIGS.8B to 8D. These sandwich plate profiles may also be referred to as nodalprofiles.

In FIG. 8B three prefabricated sandwich plate members are connectedtogether with two aligned and the third extending perpendicularly fromthem and is representative of a typical deck to side shell connectiondetail. The nodal profile 101 used to effect this connection is aroll-formed or extruded section of metal having sockets facing thedirections of the structural sandwich plate members which are to beconnected. The overall form is H-shaped with the third socket formed byflanges provided on one of the uprights of the H. A male socket profile102 forming the edge of the prefabricated structural sandwich platemembers is inserted into the nodal profile 101 and welded at weldlocations to form a continuous structure as shown in FIG. 8C. Finishingwelds (not shown) make the joint continuous. Localised welding can becarried out without affecting the structural integrity of the joint.

FIGS. 8D and 8E illustrate the method of use of two nodal profiles 103and 104 that are used to connect two prefabricated structural sandwichplate members and are again representative of a typical deck side shellconstruction detail. Nodal profiles 103 and 104 provide a right angleconnection with a square outer corner and a chamfered outer corner,respectively. In both cases, the profiles are generally U-shaped withsmall perpendicular plate protrusions on the outside face of one legwhich form the second socket.

FIG. 8F illustrates the method of use for sandwich plate profile 107that would be used to connect four prefabricated structural sandwichplate members and is representative of a typical inner hull stoolbulkhead connection.

FIG. 8G illustrates the method of use for the sandwich plate profile 106which is integrated into one structural sandwich plate member andsubsequently made continuous with two other precast structural sandwichplate members by welding at weld locations. Again, finishing welds areomitted for clarity. In this case, the nodal profile 106 is basically astructural angle with inner small plate protrusions which areperpendicular to the outside face of the legs of the angle. The smallplates provide alignment, socket and weld details for accepting twoprecast structural sandwich plate members.

Although not illustrated by any of the profiles in FIG. 8, it ispossible to vary the geometry of the profile to change the alignment ofthe prefabricated structural sandwich plate member from being orthogonalto any other angle. Also, it is preferable with all of the arrangementsof FIGS. 8A to G that finishing welds result in smooth outer surfaces tothe joints, filling in the gaps between outer plates 21 and the flangesto the nodal profiles.

Arrangements to connect angled structural sandwich plate members to eachother and to conventional plates in which at least one plate member isframed into the joint at an oblique angle are shown in FIGS. 9A to J.The connections of FIGS. 9A to G are representative of typicalconnection between a hopper, inner hull bottom and a longitudinalgirder, or between the side shell, hopper-side shell and a stringer.Those of FIGS. 9H, I and J can be used for hopper to inner hull bottomto stool connections. FIGS. 9A to E illustrate complex profiles that areintegrated into the steel fabrication process prior to the injection ofelastomer and their manner of use whilst FIGS. 9F and 9G illustratecomplex profiles that join precast structural sandwich plate members.

The working line or centroid of all plate members framing into theconnection are aligned to act through the same point so that noeccentric forces act on the profile.

FIG. 9A illustrates a basic form of a complex profile 110 which is usedto connect an inclined structural sandwich plate member, a horizontalstructural sandwich plate member and a vertical metal plate. The complexprofile 110 essentially comprises a vertical plate portion which is tobe aligned with and butt welded to a vertical metal plate at a weldlocation. Four flanges 111-114, extending from the vertical plateportion a distance sufficient to place joining welds to outer plates 61in a lower stress range region (for better fatigue resistance) arespaced apart and oriented to align with the outer plates 21 of theinclined and horizontal structural sandwich plate members. The outerplates 21 of the structural sandwich plate members are butt welded tothe respective tips of flanges 111-114. The extension of the verticalmetal plate through the core depth of the structural sandwich platemembers transmits the through-thickness forces associated with thevertical force component in the inclined structural sandwich platemember.

FIGS. 9B, 9C and 9D are variations of the basic form of the complexprofile which include different weld preparations. The flange tips offlanges 121-124 and 131-134 of complex profiles 120 and 130 in FIGS. 9Band 9C have been bevelled for full penetration groove welds to made formthe outside or all from above, respectively. Complex profile 120 in FIG.9D has integrated backing bars 145 which provide the landing surface andalignment necessary to make butt welds between the outer plates 21 andthe complex profile 140 from the preferred directions. Complex profile150 in FIG. 9E is a variant of complex profile 140 with solid core 151having side faces 152, facing the structural sandwich plate members androlled notches 153 that provide the same function as backing bars.

FIGS. 9F and 9G illustrate two additional variations of the basic formof the complex profile in FIG. 9A that would be used to joinprefabricated structural sandwich plate members to conventional metalplates. FIG. 9G illustrates the use of a solid metal block or bar 107 asan alternative male socket member to the U-shaped profile and the samesolid core variation 171 as illustrated in FIG. 9E. Although notillustrated, complex profiles may be provided that are integrated intoone or more structural sandwich plate members and provided with one ormore sockets for connection to one or more prefabricated structuralsandwich plate members.

FIGS. 9H, I and J illustrate a variety of complex profiles 180, 190, 200for typical hopper to inner hull bottom to stool connections and theirmanner of use for joining prefabricated structural sandwich platemembers and conventional metal plates. In each case, appropriatelyoriented and spaced flanges 181, 182, 191, 192, 201, 202 are provided toform sockets to receive male socket members 102, 105 provided in theends of the structural sandwich plate members and webs 183, 193, 203transmit through-thickness forces.

FIGS. 10A to C illustrate transition profiles 210, 220, 230 which areused to connect a structural sandwich plate member to an alignedconventional metal plate or web.

As shown in FIG. 10A, transition profile 210 essentially comprises twoplate portions 211, 212 which are joined together at one edge, wherethey are to be welded to the conventional metal plate 73 at a weldlocation. The upper plate portion 211 is parallel and aligned with theconventional metal plate 73 where as the lower plate portion 212 isinclined so that at the distal edges of the plate portions 213, 214 theyare spaced apart by a distance equal to the thickness of the structuralsandwich plate member to which the outer plates 21 are welded. Thedistal end portion 213 of plate portion 212 is made parallel to theother plate portion 211 and the outer plate of the structural sandwichplate member to which it is to be connected. The distal end portions ofthe plate portions 211, 212 are also provided with backing bars 214 toassist in welding the outer plates 21 of the structural sandwich platemember to transition profile 210.

Transition profile 220 shown in FIG. 10B is a very similar to transitionprofile 210 of FIG. 10 A but the upper link member 221 is shortened sothat the points of connection between plate portions 221, 222 and therespective outer plates 21 of the structural sandwich plate member arenot aligned vertically and in which an additional backing bar detail hasbeen included to facilitate the welding of the transition profile to themetal plate 73 at the weld location.

Transition profile 230 shown in FIG. 10C is for use where the existingplate 74 extends to form one of the outer plate members of thestructural sandwich plate member, as in the case of structural overlays.The lower plate portion 231 is placed against and welded at its edges toplate 74. The upper plate portion 232 is joined at one edge to one edgeof lower plate portion 231 and rises up so as to be spaced from lowerplate portion 231 for connection to plate 21 which forms the other outerplate of the structural sandwich plate member.

A fourth transitional profile 240 is shown in FIG. 10D and is simpler toroll-form. Transitional profile 240 comprises a head portion 241, a mainangled plate 242 and a tail portion 243. The head portion has a backingbar 244 and weld preparation 245 at a weld location for connection to anexisting metal plate 73 as well as a shoulder 246 to receive one outermetal plate 21 of the structural sandwich plate element. The tailportion 243 has a backing bar 247 for receiving the other outer metalplate 21 whilst the main angled plate 242 makes the transition from theexisting metal plate 73 to the full thickness of the structural sandwichplate member.

It will be appreciated that in describing the various profiles of theinvention, directional terms such as “upper”, “above” and “horizontal”,etc., have been used with reference to the orientation of the variousparts shown in the drawings. Of course, the various parts can also beused in other orientations, as desired. It will also be appreciated thatthe various profiles will be rolled or extruded with the shapes,dimensions and weld preparations that are satisfactory for bothstructural and economic considerations.

A mid-tank section of a 40,000 DWT product oil tanker 300 is shown inFIGS. 11 to 15 as an example of the use of structural sandwich platemembers and structured profiles according to the present invention. FIG.11 is a mid-tank cross section of the tanker 300 with the left hand partshowing longitudinal framing and the right hand part showing a typicaltransverse frame. FIG. 12 is a longitudinal section for a portion oftank section along a longitudinal frame. FIG. 13 is an isometricexploded view of a typical tank section. FIG. 14 is a partially explodedview with enlarged portions showing the use of profiles according to theinvention to connect a structural sandwich plate member, e.g. formingpart of the inner or outer hull, to a perpendicular plate, e.g. alongitudinal or transverse framing plate. FIG. 15 is a perspective viewof two hull sections with an enlarged portion showing the use of edgeprofiles according to the invention to join the modules.

For this particular example the deck plate 311, outer hull 302, 303,310, 314 and inner hull 304, 305, 316, 317 would be constructed withstructural sandwich plate members. The corrugated bulkhead 315,longitudinal framing 306, 307, 312 and transverse framing 308, 309, 313would be constructed with metal plates. Profiles according to thepresent invention, described above and illustrated in FIGS. 1 to 10would be used to join these members. All members are made continuous bywelding and according to the present invention a significant number ofstructural sandwich plate elements may be prefabricated and subsequentlywelded together at a weld location on site.

In particular, the plate profiles 81, 82, 83, 84 shown in FIGS. 5A to Dcan be used to connect a longitudinal or transverse framing plate 306,307, 308, 309, 312, 313 to a structural sandwich plate member 2 dforming part of the inner or outer hulls 302, 303, 304, 305, 310, 314,316, 317. An example of connection of a longitudinal framing plate isshown in greater detail in FIG. 14. As can there be seen, the structuralsandwich plate member 2 d is made up from three elongate steel plates 21a, 21 b, 21 c of which the largest 21 a forms the outermost layer of theouter hull or the innermost layer of the inner hull. Edge profiles 1 a,1 b, or 1 c are welded along the short edges of the plate 21 a, theseedges will form the edge of a hull section in which the structuralsandwich plate member 2 d is to be incorporated and facilitateconnection of hull sections as described above. Along the long edges ofthe plate 21 a, socket profiles 71, 72 are welded to facilitateconnection of the structural sandwich plate member 2 d to adjacentmembers in the hull section. The plate profile 81, 82, 83 or 84 iswelded along the centre line of plate 21 a. Plates 21 b and 21 c canthen be welded in place with the edge profiles 1 a, 1 b, 1 c, or 1 d,socket profiles 71, 72 and backing bars on the plate profile 81, 82, 83or 84 supporting the plates 21 b, 21 c. With the plates 21 b, 21 c inplace, two air-tight cavities are formed and these are then injectedwith elastomer to complete the structural sandwich plate member. Theframing plate 306, 307 can then be welded to the plate profile 81 at thewelding location which projects far enough from the structural sandwichplate member 2 d to prevent the heat of welding damaging the elastomer.It will be appreciated that the construction of the structural sandwichplate member 2 d and optionally also the connection of the longitudinalframing plate 306, 307 can be carried out in a factory rather than ashipyard, enabling improved dimensional accuracy and higher qualityconstruction through well cured elastomer and good welds.

Other examples of the use of profiles according to the invention in thevessel of FIGS. 11 to 15 are:

complex profiles 110, 120, 130, 140, 150, 160, 170 to connect inner hullbottom 305 to hopper 318 to a longitudinal framing plate 307 or innerside shell 304 to hopper 318 to a longitudinal framing plate 306;

sandwich plate profiles 101 to 107 to connect deck 311 to side shell304; and

complex profiles 180, 190, 200 to connect hopper 318 to inner hullbottom 305 to stool 316.

As mentioned above, edge profiles according to the invention can beemployed to facilitate connection of hull sections or modules of otherstructures, allowing the modules or sections to be constructed off-sitefor convenience and improved dimensional accuracy. This is illustratedin FIG. 15 which shows the connection of two hull modules 401, 402 ofthe vessel 300. The modules 401, 402 are constructed so that the edgesof the structural sandwich plate members which form the edges of thesections are provided with edge profiles 1 c. When the two modules 401,402 are brought together, the free edges of the long flanges 11 of theedge profiles 1 c can be displaced as necessary to line up against theend of the short flange of the edge profile 1 c on the other section.Simply welding the long flanges to the short flanges at the weldlocation assisted by the built-in weld preparations, joins the twosections and forms cavity 5 which is subsequently injected withelastomer to form a composite structure.

Whilst we have described above exemplary embodiments of the invention,it will be appreciated that this description is not intended to belimitative and that variations and modifications may be made to thedescribed embodiments without departing from the scope of the inventiondefined in the appended claims.

1. A structural sandwich plate member comprising: a first outer metalplate including a left side plate and a right side plate and a secondouter metal plate; an unfoamed polyurethane elastomer core bonded tosaid outer metal plates with sufficient strength to transfer shearforces therebetween; and a rolled or extruded edge member fitted betweenand connected to said first and second outer metal plates and extendingalong at least a part of the periphery of said outer metal plates andsaid profile providing a weld location suitable for welding saidstructural sandwich plate member to another structural sandwich platemember, said edge member comprising: a web extending perpendicularly tosaid first and second outer metal plates and having a first end and asecond end, and a first flange disposed intermediate the first andsecond ends, the second end being welded to said second outer metalplate, the web extending from said second end to said first flange incontact with said polyurethane elastomer core, wherein the first flangeis substantially parallel to said first outer metal plate in contactwith said polyurethane elastomer core and welded to surfaces of saidleft side plate and said right side plate of said first outer metalplate that face the second outer metal plate, the web extending fromsaid first flange in a direction away from said polyurethane elastomercore and perpendicularly to said first metal plate beyond said firstflange and said first and second outer metal plates to said first end.2. A structural sandwich plate member according to claim 1 wherein saidedge member comprises: a second flange extending parallel to said firstflange from said second end of said web and at least partially lyingagainst said second outer plate.
 3. A structural sandwich plate memberaccording to claim 2 wherein said web is upstanding from one edge ofsaid first flange.
 4. A structural sandwich plate member according toclaim 3 wherein said edge member further comprises a third flangesubstantially parallel to said first flange and projecting from said webin the opposite direction to said first flange, said third flange beingpositioned to act as a backing bar for welding said first outer plate tosaid edge member.
 5. A structural sandwich plate member according toclaim 2 wherein at least one edge of said first flange is provided withpreparations for butt welding to another flange or plate.
 6. Astructural sandwich plate member according to claim 2 wherein saidsecond flange extends beyond the edge of said second outer plate to actas a support for welding another plate or flange to said structuralsandwich plate member.
 7. A structural part comprising at least firstand second structural sandwich plate members, said first structuralsandwich plate member including a first outer plate including a leftside plate and a right side plate and a second outer metal plate, anunfoamed polyurethane elastomer core bonded to said outer metal plateswith sufficient strength to transfer shear forces therebetween, and arolled or extruded edge member fitted between and connected to saidfirst and second outer metal plates and extending along at least a partof the periphery of said outer metal plates, and said edge memberproviding a weld location suitable for welding said structural sandwichplate member to another structural sandwich plate member, said edgemember comprising a web extending perpendicularly to said first andsecond outer metal plates and having a first end and a second end, and afirst flange disposed intermediate the first and second ends, the secondend being welded to said second outer metal plate, the web extendingfrom said second end to said first flange in contact with saidpolyurethane elastomer core, wherein the first flange is substantiallyparallel to said first outer metal plate in contact with saidpolyurethane elastomer core and welded to surfaces of said left sideplate and said right side plate of said first outer metal plate thatface the second outer metal plate, the web extending from said firstflange in a direction away from said polyurethane elastomer core andperpendicularly to said first metal plate beyond said first flange andsaid first and second outer metal plate to said first end, said secondstructural sandwich plate member comprising first and second outer metalplates and an elastomeric core bonded to said outer metal plates withsufficient strength to transfer shear forces therebetween, and saidfirst and second structural sandwich plate members being joined togetherby welding along said edge member.